In situ acetylation dispersive liquid–liquid microextraction followed by gas chromatography–mass spectrometry for the simultaneous determination of musks, triclosan and methyl-triclosan in wastewaters

A rapid and environmental-friendly analytical method for the simultaneous analysis of different personal care products (PCPs) namely synthetic musks (nitro-, polycyclic and macrocyclic musks) and the disinfectant triclosan (TCS) and its transformation product methyl-TCS in wastewater samples has been developed. The method combines dispersive liquid–liquid microextraction with in situ aqueous derivatisation using acetic anhydride (Ac2O) prior to gas chromatography–mass spectrometry analysis. Several parameters affecting both extraction and derivatisation efficiency (e.g. type and volume of extractor and dispersive solvents, volume of derivatising reagent, etc.) were optimised to achieve reliable conditions. Validation of the method for all compounds under study showed good linearity with coefficient of correlation > 0.9947. Limits of quantification (LOQs) ranged between 2 and 72 ng/L for musks and 28 and 31 ng/L for TCS and methyl-TCS, respectively. Accuracy, expressed as the average recoveries, ranged between 76% and 87%, and precision, expressed in terms of intraday repeatability (%RSD), was better than 13% for all analytes. The application of the method to the analysis of 24 wastewater samples enabled the detection of all the target PCPs at concentration levels up to 2.7 μg/L, being galaxolide (HHCB) and tonalide (AHTN) the more prevalent, present in 88% and 46% of the samples, respectively.